To link to the entire object, paste this link in email, IM or documentTo embed the entire object, paste this HTML in websiteTo link to this page, paste this link in email, IM or documentTo embed this page, paste this HTML in website

"# 745 Drilling Jumbo in operation in the face of one
of the Diversion Tunnels. From 20 to 25 drills can be operated at once and one-half of the face drilled in one operation. December 8th, 1931.
# 671 View of the drilling Jumbo taken outside the
Diversion Tunnels. It is of welded steel con¬struction, mounted on a truck chassis. December 13th, 1931.
# 747 Another view of a drilling Jumbo, backed up to the tunnel--face, showing the method of con¬struction and mounting. December 8th, 1931.
# 748 100-ton Marion Electric Shovel excavating blasted rock from one of the Diversion Tunnels. A three-and a half cubic yard dipper is used on these shovels. December 8th, 1931."

"# 745 Drilling Jumbo in operation in the face of one
of the Diversion Tunnels. From 20 to 25 drills can be operated at once and one-half of the face drilled in one operation. December 8th, 1931.
# 671 View of the drilling Jumbo taken outside the
Diversion Tunnels. It is of welded steel con¬struction, mounted on a truck chassis. December 13th, 1931.
# 747 Another view of a drilling Jumbo, backed up to the tunnel--face, showing the method of con¬struction and mounting. December 8th, 1931.
# 748 100-ton Marion Electric Shovel excavating blasted rock from one of the Diversion Tunnels. A three-and a half cubic yard dipper is used on these shovels. December 8th, 1931."

"# 745 Drilling Jumbo in operation in the face of one
of the Diversion Tunnels. From 20 to 25 drills can be operated at once and one-half of the face drilled in one operation. December 8th, 1931.
# 671 View of the drilling Jumbo taken outside the
Diversion Tunnels. It is of welded steel con¬struction, mounted on a truck chassis. December 13th, 1931.
# 747 Another view of a drilling Jumbo, backed up to the tunnel--face, showing the method of con¬struction and mounting. December 8th, 1931.
# 748 100-ton Marion Electric Shovel excavating blasted rock from one of the Diversion Tunnels. A three-and a half cubic yard dipper is used on these shovels. December 8th, 1931."